The present invention is directed to paper fasteners, and in particular, to paper clip apparatus.
The typical paper clip is capable of securely fastening only a few layers of material in a reliable manner. As the number and/or thickness of the layers increases, the gripping and holding power of the typical paper clip decreases. This is because the "U"-shaped portions which are the "legs" of the clip, become more and more spread apart, and the included angle between the legs increases, leaving less and less surface area of the legs in actual contact with the upper and lower layers of the bundle or packet of material being held together. Eventually, the included angle becomes so great, and the amount of useful surface area becomes so small, that the inherent resiliency of the clip will tend to propel the clip off of the bundle or packet, even if the bundle or packet is not being handled. If the bundle of materials are being handled, and individual layers being lifted, then the clip may tend to dislodge with even fewer or thinner layers present in the bundle.
A number of modifications of the standard paper clip have been attempted, seeking to improve their gripping power and resistance to dislocation. For example, the free ends have been turned outwardly from the "plane" of the clip, and/or pointed, as shown in U.S. Pat. Nos. 2,299,496 to Rolfson, or 2,947,047 to Guzell. Other prior art clips have had serrated surfaces, Rolfson '496 or U.S. Pat. No. 5,170,535 to Strong, or wave-like distortions or flattened surfaces, as in U.S. Pat. No. 3,057,027 to Bugge, in order to increase the surface area of the clip which is in contact with the layers to be held together. Still other prior art devices have employed locking type configurations, U.S. Pat. No. 3,840,943 to Langwell, or unusual scissor-like or clamping configurations, as in U.S. Pat. No. 4,523,354 to Tsukamoto or No. 5,022,124 to Yiin, respectively.
Yet another prior art device, disclosed in Walker, U.S. Pat. No. 3,913,181, provides a coating to the loop surfaces of the clip, so as to raise the coefficient of friction to help enhance the gripping power and resistance to dislodging of the clip. The usefulness of the coating is still limited by the fact that, as the thickness of the bundle increases, less and less of the surface area of the clip, and thus less and less of the surface area of the coating, makes contact with the layers, Accordingly, the full potential of the frictional coating cannot be utilized.
It is an object of the invention to provide an improved clip apparatus which is capable of usefully holding a greater thickness of layers of material, than conventional standard paper clips.
Another object of the invention is to provide an improved clip apparatus which has increased resistance to dislodging from the articles being clipped.
Still another object of the invention is to provide an improved clip apparatus which is inexpensive and simple to manufacture.
These and other objects of the invention will become apparent in light of the present specification, claims and drawings.